Startechcom 2 port pci express pcie to rs 232 serial cards startechcom pex2s553lp the startechcom pex2s553lp low profilehalf height pci express serial card turns a pci express slot into 2 x rs232 db9 serial connections the card is constructed using a native single chip design that lets you harness the full capability offered by pci express pcie while reducing the load applied to the cpu by as much as 48 over conventional bridge chip serial cardsthe pci express rs232 serial adaptor